<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <title>Document</title>
</head>
<body>
    <div id="root">
        <h2>今天天
            {{isHot?'炎热':'凉爽'}}</h2>
        <button @click="isHot=!isHot">切换天气</button>
    </div>
    <script>
        new Vue({
            el:"#root",
            data:{
            isHot:false
            },
            methods:{ 
                // chengfun(){
                //     this.isHot=!this.isHot
                // }
            }
        })
    </script>
</body>
</html>